In wireless mesh networks, multiple devices or “nodes” communicate wirelessly with one another by sending and receiving wireless messages, which are often radio frequency (RF) messages that conform to a protocol, such as IEEE Standard 802.11. Mesh networks allow the nodes of the network to communicate with one another without the direct exchange of RF messages between the two nodes in communication. For example, two devices that are not within range of each other may communicate via one or more other nodes in the network. Wireless messages are received at a node and re-transmitted, such that the message is passed from node to node until the message reaches the destination node. Since there may be many suitable paths through the mesh network, wireless mesh networks can be more robust than traditional wireless networks. For example, if a node along a chosen path fails, the message can be rerouted through a different path. Such rerouting may be performed automatically, enabling the wireless mesh network to be self-healing in response to node failures. Another advantage of wireless mesh networks is that they can reduce the need for fixed infrastructure, as nodes can communicate with one another at a distance without the need for fixed access points.
One difficultly with mesh networks is that of coordinating the transmissions of various devices that are in the vicinity of one another. If multiple devices near each other transmit at the same time, the transmissions may interfere with one another and reduce the data rate that is achievable. To prevent this type of interference, various types of media access control (MAC) protocols can be used. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is one such MAC protocol, in which a device informs other nodes in the vicinity of its intent to transmit, prior to transmitting. Upon receiving notice that a device intends to transmit, the other nodes in the vicinity then wait to transmit, so as to avoid transmitting at the same time, thereby reducing the likelihood of interfering transmissions.